In this four-part serial from 1980, Peter Curtis (perennial bad guy Ian McShane) leaves prison after serving four years for manslaughter. His victim's enigmatic last words were "High tide's at 9:52," and now Peter seeks to find out why. Heading south, he books into a hotel where the only other resident knows all about him, and then picks up a hitchhiker who may be far from innocent. As Peter searches the tidal estuaries of West England, he comes up against far greater dangers than treacherous currents: other people, it seems, are interested in those last words and are prepared to kill to solve the mystery.